Coolant heater and control unit construction



Dec. 5., 1961 G. E. WEHL COOLANT HEATER AND CONTROL UNIT CONSTRUCTION Filed Oct. 5, 1959 INVENTOR.

BY Glen/10E. Whl $4M, W2 M ATTORNEYS United States Patent 3,012,129 COOLANT HEATER AND CONTROL UNIT CONSTRUCTION Glenn E. Wehl, North Canton, Ohio, assignor to Creativeering Inc., Canton, Ohio, a corporation of Ohio Filed Oct. 5, 1959, Ser. No. 844,252 2 Claims. (Cl. 219-39) My invention relates to a unit for heating and controlling the flow of'coolant liquids used in the coolant sprays of dental handpieces. More specifically, my invention in coolant heater and control unit construction is particularly useful for supplying coolant to the modern high speed fast-cutting dental handpieces, such as the recently-developed air turbine dental handpieces which require increased supplies of the coolant liquids.

Certain prior dental units have been provided with relatively large liquid reservoirs in which water is stored and maintained at a given desired temperature. Usually, it has been from such reservoirs that the coolant required for the coolant sprays on the dental handpieces have been taken and with the previous forms of electrically driven handpieces, where the amounts of coolant required have not been relatively small, these arrangements have been satisfactory.

Furthermore, in these prior dental units the flow of coolant to the coolant spray on the handpiece has frequently been controlled by a valve actuated by the dentist or even by the patient upon which the dental work is being performed. Again, this has been satisfactory with the relatively slow former electrically driven handpieces in view of the fact that little material is removed at a time and the heat build-up is relatively slow in the patients teeth.

With the relatively recent advent of the extremely high speed fluid turbine dental handpieces, however, a much greater flow of coolant is required, not only to quickly wash away the material being removed from the patients tooth, but also to maintain the temperature of the tooth within a range comfortable to the patient.

Thus, it is necessary to provide, first, a control for the flow of coolant which is automatically actuated when the handpiece is actuated and stopped when the handpiece is stopped. Secondly, in order to provide a millcient amount of the coolant, it is necessary to either provide an extremely large reservoir of preconditioned water or other coolant, or to provide some means for quickly and steadily conditioning the coolant as it passes therethrough to the handpiece.

Further, it is not possible to use coolant such as water directly from the usual source of supply since the temperature must be raised a certain amount in order to prevent discomfort to the patient when the coolant is sprayed on the tooth upon which the work is being per formed. Thus, the conditioning of the coolant, such as water, requires that it be heated, and unless an undesirable relatively large reservoir of the water is maintained, it is necessary to quickly heat the water as it passes through a relatively small tank.

It is, therefore, a general object of the present invention to provide a coolant heater and control unit construction which eliminates the disadvantages of the prior constructions, solves the foregoing problems, and is adapted for use with modern dental handpiece equipment.

It is a primary object of the present invention to provide a coolant heater and control unit construction which is self-contained in one compact assembly and serves the three-fold purpose of quickly heating coolant passing therethrough, heating the coolant to a desired temperature range, and controlling the flow of coolant to the coolant spray on the dental handpiece.

It is a further object of the present invention to provide a coolant heater and control unit construction which makes use of a unique form of coolant tank in which the coolant may be quickly and efliciently heated to the desired temperature while passing therethrough.

-It is still a further object of the present invention to provide a coolant heater and control unit construction in which the entire combined unit may be provided as one assembly, with any problems of sealing the electrical controls for the heating elements from the coolant tank being virtually eliminated.

Finally, it is an object of the present invention to provide a coolant heater and control unit construction which satisfied all of the foregoing objects and yet may be manufactured and assembled at a minimum of expense.

These and other objects are accomplished by the parts, constructions, arrangements, combinations and subcombinations comprising the present invention, the nature of which is set forth in the following general statement, a preferred embodiment of Which-illustrative of the best mode in which applicant has contemplated applying the principlesis set forth in the following description and illustrated in the accompanying drawings, and which is particularly and distinctly pointed out and set forth in the appended claims forming a part hereof.

In general terms, the coolant heater and control unit construction comprising the present invention may be stated as including a main housing formed preferably of three sections defined as an electrical control section, a tank section and a fluid control section. A closed fluid tank is formed by the tank section by a preferably hollow cylindrical side wall, a circular top wall and a circular bottom wall, with the electrical control section preferably being mounted overlying the tank top wall and the fluid control section preferably being mounted underlying the tank bottom wall. The three sections are in this manner preferably joined into a single compact unit.

The electrical control section preferably includes a heating control switch, a selectively adjustable thermostat, and a heating coil preferably in the form of a sealed rod-like heating coil unit. Further, the heating coil unit is positioned in the tank of the tank section for heating fluid in the tank and passing therethrough.

Electrical transmission connections are provided from a source of electrical power through the heating control switch through the thermostat and to the heating coil for providing electrical power to the heating coil. The temperature of the fluid in the tank of the tank section thereby actuates the thermostat with the thermostat controlling the electrical power to the heating coil and in this manner maintaining the temperature of the fluid in the tank at within desired temperature range.

The tank section is preferably provided with a well portion completely fluid-sealed from the confines of the tank, but adjacent thereto, with this well portion preferably opening into the electrical control section. The rod-like heating coil is received mounted in the well portion with the electrical connections thereto projecting into the electrical control section.

Furthermore, the well portion formed in the tank section is preferably provided with a series of spaced fins projecting into the inner confines of the tank, preferably terminating spaced from the tank section side wall and surrounded at certain portions thereof by the fluid in the tank, for efficiently transmitting heat from the heating coil of the electrical control section through the portion of the tank section forming the well portion, through the fins and into the fluid contained in the tank. Also, the tank section is provided with fluid inlet and fluid outlet openings with the fluid inlet being connected to a main supply of fluid coolant and the fluid outlet being connected to the fluid control section.

The fluid control section includes a normally closed electrically actuated solenoid valve which is open when actuated. The electrical controls for the solenoid valve are connected to a main control member which also preferably controls the actuation of a dental handpiece.

The fluid control section is further provided with fluid inlet and outlet openings operably connected to the solenoid valve with the solenoid valve permitting the flow of fluid therethrough from the fluid inlet to the fluid outlet when actuated and interrupting the flow of fluid therethrough when not actuated. fluid inlet of the fluid control section is operably connected to the fluid outlet of the tank section, and the fluid'outlet of the fluid control section is operably connected to the coolant spray of the dental handpiece.

By way of example, an embodiment of the coolant heater and control unit construction of the present invention is illustrated in the accompanying drawings forming a part hereof, wherein like numerals indicate similar parts throughout the several views and in which:

FIG. 1 is a vertical sectional view, part in elevation, showing the embodiment of the coolant heater and control unit completely assembled;

FIG. 2, a sectional view, part in elevation, looking in the direction of the arrows 22 in FIG. 1; and

FIG. 3, a sectional view, part in elevation, looking in the direction of the arrows 33 of FIG. 1.

The embodiment of the coolant heater and control unit construction comprising the present invention preferably includes an electrical control section, generally indicatedat 10, a tank section, generally indicated at 11, and a fluid control section, generally indicated at 12, all of which are preferably generally hollow cylindrical in configuration with the main wall portion thereof prefably being formed of cast aluminum. Furthermore, the electrical control section is preferably mounted overlying the tank section 11, and the fluid control section 12' is preferably mounted underlying the tank sec- Finally, the

tion 11, as shown, to thereby provide a maximum of i compactness for the unit. 7

The electrical control section 10 is preferably mounted in a generally hollow cylindrical cap member 13 having the hollow cylindrical sidewall 14 and the circular top wall 15. Cap member 13 is preferably mounted on the top Wall 16 of the tank section 11 by means of the preferably brass stud 17, which stud is secured to the electrical control section top wall 15 by means ofthe nut 18, passes preferably centrally through the electrical control section 10 and is secured into the top wall 16 of the tank section '11, as shown.

Thus, the electrical control section 10 is mounted overlying the top wall 16 of the tank section 11 and opens downwardly to this top wall16. A main heating control switch 19 is mounted on the top wall 15 of this electrical control section it! and extends through top wall 15 for access at the outer side of the top Wall.

A conventional electrical thermostat 20,,which may be of the usual bimetal type, is preferably mounted on the stud 17 spaced slightly above the top wall 16 of tank Section 11, with the adjustable control 21' for thermostat extending through the top wall 15 of the electrical control section 10, being accessible at the outer side of this top wall similar to the switch 19. Finally, the electrical control section 10 includes the electrical heating coil 22 which is preferably generally cylindrical rod-like'in configuration, of the usual sealed type, and is positioned extending into the tank section 11. i

The tank section 11 is preferably formed of two por- V are formed for insertion into the cup-like portion formed The well portion extends within the side wall 23 7 preferably from the top wall 16 to the bottom wall 24, with the remainder of this tank section outwardly of the well portion 25 and within the side wall 23 defining a closed fluid tank 26. Further, preferably two spaced heat transmission fins 27 are integrally connected to the wall portion 25'extendin'g into the 'tank 26 and preferably between the top Wall 16 and bottom wall 24 but preferably spaced from the side wall ,23 suflicient to permit the circulation of fluid therearound and within the tank 26. g V

The well portion 25 is provided with a well or opening wardly into the electrical control section 10, with this well 28 receiving the rod-like'heating coil 22 therein for positioning the heating coil scaled from the fluid of tank 26 but closely adjacent thereto for easy transmission of heat to this fluid in the tank. Finally, the tank 26 is provided with a fluid inlet opening 29 preferably at the lower portion thereof near the bottom wall 24 and a fluid outlet opening 30 preferably at the upper portion thereof near the top wall 16.

The fluid control section 12 preferably opens upwardly toward the bottom wall 24 of the tank section 11 with this fluid control section having .the generally hollow cylindrical, but slightly tapered, side wall 31 and'closed bottom wall 32. A conventional electrically controlled fluid. solenoid valve 33 is mounted within the side wall 31 above the bottom wall 32 and is operably connected in communication with a fluid inlet opening 34- and a fluid outlet opening 35. Solenoid valve 33 is open when actuated permitting the flow of fluid from the fluid inlet 34 to the fluid outlet 35 and is closed when not actuated, interrupting the flow of fluid between the fluid inlet and fluid outlet. r

Preferably, a flexible tube 36 is connected from a sourcerof fluid coolant, not shown, to thefluid inlet 29 of tank 26 in the tank section 11, and also a preferably flexible tube 37 is connected from the tank fluid outlet 30 of tank section 11 to the fluid inlet 34-of the fluid control section 12. Further, a preferably [flexible tube 38 is connected from the fluid outlet 35 of the fluid control section 12 to the coolant spray of a dental handpiece,

not shown.

Still further, an electrical transmission line 32 is connected from a main source of electrical power, not shown, through the heating control switch 19, the thermostat 20 andfto the heating coil 22 in usual manner.

Finally, an electrical transmission line 40 is connected I from a main source of electrical power, not shown, preferably through the same control controlling the dental 'handpiece, not shown, and to the solenoid valve 33.

'I'hus,the heating coil 22 is energized to heat fluid coolant contained in and passing through the tank 26, and the temperature of the fluid coolant in tank 26 may be selectively controlled within desired temperature ranges through the thermostat 2t) and the adjustable control 21 therefor. Further, by actuation of the solenoid valve 33, the heated fluid coolant may be transmitted from the tank 26 to the coolant spray on the dental handpiece when the main controls for the dental handpiece are actuated to thereby actuate the solenoid valve 33. t

The coolant heater and control unit as shown and described above may be separately attached toa dental unit, not shown, by means of a usual bracket 41, where it is desired to add this unit to an already-existing dental unit when, for instance, air turbine dental handpieces are added to the unit requiring the larger supplyof coolant as previously discussed. It should be understood, however, that it is notintended to. limitthe principles of the present invention merely to a separately attaching unit, but this unit may be .incorporated originally in an over-all dental unit as desired.

An important feature of the present invention is the compactness of the over-all coolant heater and control unit and the fact that large amounts of coolant may be supplied in a desired heated condition with this unit. One portion of the construction which is important to the eflicient heating of the fluid coolant in the tank 26 is the provision of the heating transmission fins 27 projecting from the well portion 25 into the tank 26 which supply an eflicient heat transmission from the heating coil 22 mounted in this well portion.

A further important feature of construction is the provision of the sealed well portion 25 which is closely adjacent the tank 26 but yet is completely sealed from the fluid coolant contained in the tank, thereby virtually eliminating all sealing problems. Furthermore, the well or opening 28 formed in the well portion 25 and opening upwardly into the electrical control section within which the heating coil 22 is mounted, provides an efiicient positioning for the heating coil to heat the fluid coolant in tank 26, yet this heating coil is easily accessible from the electrical control section 10 without disassembling any portion of the tank section 11.

In the foregoing description, certain terms have been used for brevity, clearness and understanding, but no unecessary limitations are to be implied therefrom, because such words are used for descriptive purposes herein, and are intended to be broadly construed.

Moreover, the embodiment of the improved construction illustrated and described herein is by way of example, and the scope of the present invention is not limited to the exact details of the construction shown.

Having now described the invention, the construction, operation and use of a preferred embodiment thereof, and the advantageous new and useful results obtained thereby; the new and useful construction and reasonable mechanical equivalents thereof obvious to those skilled in the art are set forth in the appended claims.

I claim:

1. Coolant heater and control unit construction including an electrical control section and a tank section and a fluid control section; the tank section including a one piece cup-like tank member having closed side and bottom walls and a top opening forming an upwardly opening tank, fluid inlet and fluid outlet openings formed communicating into the tank member, an insert member mounted on the tank member having a top wall closing the tank member top opening and a downwardly extending heater portion extending downwardly from the top wall and into the inner confines of the tank member, and a heater well formed within the heater portion opening upwardly through the top wall and fluid sealed by the heater portion from the inner confines of the tank member; electrical heating coil means positioned in the insert member heater well for heating liquid contained in and flowing through the inner confines of the tank member; the electrical control section including a cap member mounted over the top opening of the tank member and the top wall of the insert member, the cap member having a top wall spaced above the insert member top wall, and thermostat means mounted between the cap member and insert member top walls adjacent the insert member top wall for controlling the temperature of fluid within the confines of the tank member through control of the heating coil means; electrical transmission means for connection to a source of electrical power extending into the electrical control section cap member operably connected through the thermostat means and to the heating coil means within the heater well of the tank section insert member; the fluid control section including a solenoid valve having fluid inlet and fluid outlet openings, the fluid control section being mounted on the tank member of the tank section; electrical control means operably connected to the solenoid valve of the fluid control section for controlling opening of said solenoid valve for a flow of fluid therethrough from the fluid inlet to the fluid outlet openings and controlling closing of the solenoid valve interrupting the flow of fluid therethrough; fluid transmission means foroperable connection from a supply of fluid to the tank means fluid inlet opening and operably connected from the tank means fluid outlet opening to the solenoid valve fluid inlet opening and for operable connection from the solenoid valve fluid outlet opening to a coolant spray on a dental handpiece and the like for transmitting fluid to the tank member and from the tank member to the solenoid valve and from the solenoid valve to a dental handpiece and the like; stud means extending through the cap member top wall of the electrical control section and into the insert memher top wall of the tank section for mounting the cap member on the tank section; and said stud means also mounting the thermostat means within the electrical control section adjacent the insert member top wall of the tank section.

2. Coolant heater and control unit construction including an electrical control section and a tank section and a fluid control section; the tank section including a one piece cup-like tank member having closed side and bottom walls and a top opening forming an upwardly opening tank, fluid inlet and fluid outlet openings formed communicating into the tank member, an insert member mounted on the tank member having a top wall closing the tank member top opening and a downwardly extending heater portion extending downwardly from the top Wall and into the inner confines of the tank member, and a heater well formed within the heater portion opening upwardly through the top wall and fluid sealed by the heater portion from the inner confines of the tank member; electrical heating coil means positioned in the insert member heater well for heating liquid contained in and flowing through the inner confines of the tank member; the electrical control section including a cap member mounted over the top opening of the tank member and the top wall of the insert member, the cap member having a top Wall spaced above the insert member top wall, and thermostat means mounted between the cap member and insert member top walls adjacent the insert member top wall for controlling the temperature of fluid within the confines of the tank member through control of the heating coil means; electrical transmission means for connection to a source of electrical power extending into the electrical control section cap member operably connected through the thermostat means and to the heating coil means within the heater well of the tank section insert member; the fluid control section including a solenoid valve having fluid inlet and fluid outlet openings, the fluid control section being mounted on the tank member of the tank section; electrical control means operably connected to the solenoid valve of the fluid control section for con trolling opening of said solenoid valve for a flow of fluid therethrough from the fluid inlet to the fluid outlet openings and controlling closing of the solenoid valve interrupting the flow of fluid therethrough; fluid transmission means for operable connection from a supply of fluid to the tank means fluid inlet opening and operably connected from the tank means fluid outlet opening to the solenoid valve fluid inlet opening and for operable connection from the solenoid valve fluid outlet opening to a coolant spray on a dental handpiece and the like for transmitting fluid to the tank member and from the tank member to the solenoid valve and from the solenoid valve to a dental handpiece and the like; the fluid control section including side wall and closed bottom wall within which is mounted the solenoid valve; a series of spaced fins mounted on the insert member heater portion extending into the confines of the tank member for transmitting heat from the heating coil means through the insert member heater portion and fins into'the inner confines of the tank member to heat fluid in the tank member; stud means extending through the cap member top Wall of the electrical contr'ol section and into the insert member top wall of the tank section for mounting the cap member on the tank section; and said stud means also mounting the'th'ermrostat means within the elect'ricalcontrol section adjacent the insert member top wall of the tank section.

UNITED STATES PATENTS Shoenberg Feb. 19,1924 Scanlan Nov. 27, 1928 Monnot Dec. 11, 1934 Henschel .Dec. 11, 1945 Andrus Mar. 12, 1957 

